GEANT321/ggeom/gvsign.F

   1 *
   2 * $Id$
   3 *
   4 * $Log$
   5 * Revision 1.1.1.1  1995/10/24 10:20:57  cernlib
   6 * Geant
   7 *
   8 *
   9 #include "geant321/pilot.h"
  10 *CMZ :  3.21/02 29/03/94  15.41.31  by  S.Giani
  11 *-- Author :
  12 *
  13       INTEGER FUNCTION GVSIGN (XYZ, C0, C, NC)
  14 ************************************************************************
  15 *                                                                      *
  16 * Calculate the sign of the given point in relation          YB 870424 *
  17 * to the  surface                                            VP 880312 *
  18 *                                                                      *
  19 * Input :       XYZ -  point to be tested                              *
  20 *               C0  -  first coefficient of surface                    *
  21 *               C   -  coefficients of surface in the standart form    *
  22 *                      ,the first one is taken from C1                 *
  23 *               NC  -  number of coefficients (4,7, 10)                *
  24 *                                                                      *
  25 * Output :     -1, 0, +1  depending on side                            *
  26 *                                                                      *
  27 ************************************************************************
  28       COMMON /SLATE/ SLATE (40)
  29       INTEGER        ISLATE(40)
  30       EQUIVALENCE    (SLATE,ISLATE)
  31       REAL           XYZ(3), C(0:9)
  32       EQUIVALENCE    (TMP,SLATE(1))
  33 *-----------------------------------------------------------------------
  34
  35 #if defined(CERNLIB_GVCONT)
  36       NSIGN = NSIGN + 1
  37 #endif
  38 *
  39       GO TO (10013,10002,10013,10004,10013
  40      +,      10013,10007,10013,10013,10010),NC
  41 10013 CALL ZFATAM('GVSIGN. WRONG length')
  42 *
  43 *               special simple case
  44 10002 IAX   = C(1)
  45       IF (IAX.LE.3)             THEN
  46 *               X,Y,Z boundary
  47         TMP = C0 + XYZ(IAX)
  48       ELSE
  49 *               Rxy boundary
  50         TMP = -C0**2 + XYZ(1)**2 + XYZ(2)**2
  51       ENDIF
  52       GO TO 10090
  53 *               plane boundary
  54 10004 TMP   = C0+C(1)*XYZ(1)+C(2)*XYZ(2)+C(3)*XYZ(3)
  55       GO TO 10090
  56
  57 *               2nd order boundary, short case
  58 10007 TMP   = C0
  59      ++XYZ(1)*(C(1)+C(4)*XYZ(1))
  60      ++XYZ(2)*(C(2)+C(5)*XYZ(2))
  61      ++XYZ(3)*(C(3)+C(6)*XYZ(3))
  62       GO TO 10090
  63 *               2nd order boundary, general case
  64 10010 TMP   = C0
  65      ++XYZ(1)*(C(1)+C(4)*XYZ(1)+C(7)*XYZ(2))
  66      ++XYZ(2)*(C(2)+C(5)*XYZ(2)+C(8)*XYZ(3))
  67      ++XYZ(3)*(C(3)+C(6)*XYZ(3)+C(9)*XYZ(1))
  68 *
  69 10090 IS    = -1
  70       IF (TMP.GE.0.)            IS = 1
  71 *
  72   999 GVSIGN = IS
  73       RETURN
  74       END